Exemestane (AKA Aromasin)

Overview and History of Aromasin

Aromasin belongs to a category and class of medications known as aromatase inhibitors (AIs).

Aromatase inhibitors belong to a broader class of medications known as anti-estrogens.

Other subcategories of drugs in the anti-estrogen class are selective estrogen receptor modulators (SERMs), such as Nolvadex and Clomid.

Aromatase inhibitors and SERMs make up the class of anti-estrogens.

Aromatase inhibitors differ significantly from SERMs in their mode of action and how they address the issue of estrogen regulation.

There is a serious misconception that has perpetuated anabolic steroid use and the bodybuilding community for many years, but in the last 10-15 years the explanation has become much clearer.

It is a misconception and myth that SERMs like Nolvadex and Clomid act to lower estrogen levels.

This misconception likely stems from the fact that SERMs are also called “estrogen blockers,” so many people have misunderstood “estrogen blocking” to mean “estrogen elimination,” which couldn't be further from the truth.

SERMs only block the action of estrogen in some tissues in the body by occupying the receptor site in place of estrogen, preventing estrogen itself from exerting its effects at that site through receptor site binding, for example by blocking the action of estrogen at a receptor site in breast tissue.

SERMs also act as estrogen at the receptor site in other cells in other parts of the body (e.g., the liver in the case of Nolvadex).

This is where the “selective” part of “selective estrogen receptor modulator” comes into play.

However, SERMs do not lower circulating levels of estrogen in the plasma.

Aromatase inhibitors are compounds that do this by eliminating the production of estrogen by binding to and neutralizing the aromatase enzyme, the enzyme that converts (or aromatizes) androgens into estrogen.

Aromasin is a very strong and potent steroidal aromatase inhibitor of the suicidal type, and its package insert states that it reduces estrogen levels by 85%, as demonstrated in a study of breast cancer patients.[1][2] Aromasin is a drug that works by permanently inactivating the aromatase enzyme.

Suicide aromatase inhibitors like Aromasin (Exemestane) work by permanently inhibiting and neutralizing the aromatase enzyme from binding[2].

This makes the enzyme inactive forever.

The body will eventually produce more aromatase enzymes, but the currently bound enzyme will be bound indefinitely, eliminating the risk of estrogen rebound.

This is a phenomenon not seen with the other two leading aromatase inhibitors (Arimidex and Letrozole), which are non-lethal aromatase inhibitors that only bind to the aromatase enzyme for a limited time before being metabolized.

If a non-lethal aromatase inhibitor is stopped too abruptly, the circulating inhibited aromatase enzyme that has not been metabolized in vitro becomes free again and begins to aromatize androgens into estrogen at a rapid rate.

This is not the case with aromasin, however.

Exemestane was initially designed by Pharmacia & Upjohn for the treatment of female breast cancer patients, particularly postmenopausal patients, and is used as an adjuvant therapy when other first-line breast cancer treatments (such as Nolvadex) have failed.

Shortly after its development, the FDA approved Aromasin (Exemestane) for use in the prescription drug market in 1999, and it began selling under the brand name Aromasin in 2000.

Since its initial launch, its use and sales have spread worldwide and it is available in almost every country in the world.

Due to various patent and marketing/production laws, the Aromasin brand is currently the only officially manufactured and sold Aromasin product, and is very widely used worldwide.

The standard dose of Aromasin (Exemestane) is 25 mg and is sold as a 25 mg tablet, but studies have shown that it can be effective at doses as low as 2.5 mg daily.

It stands to reason that the properties and effects of aromasin could be beneficial to athletes using anabolic steroids for estrogen control.

Its use among athletes using anabolic steroids is to control almost all estrogen-related side effects, namely the appearance of gynecomastia, water retention and bloating, and elevated blood pressure (as a result of estrogen-induced increased water retention).

This is in contrast to SERMs like Nolvadex, which only act to block gynecomastia.

Like many aromatase inhibitors, Aromasin has also been proven to increase the level of endogenous testosterone production in men, which will be discussed further in this profile.

While many anabolic steroid users and bodybuilders consider Aromasin to be far more effective and far more useful (due to its suicide suppression effects) than Arimidex, Arimidex is still far more popular in the anabolic steroid use community today.

This is due to the fact that Arimidex was developed and released before Aromasin, so bodybuilders and athletes were able to recognize the anabolic steroid sooner.

To some extent, Aromasin (Exemestane) was overlooked and missed by many.

Today, things are changing as many people are beginning to recognize the superiority and advantages of Aromasin over Arimidex (which will be discussed in detail throughout this profile).

Some of the advantages that are not seen with other aromatase inhibitors include inhibition of suicide, promotion of IGF-1 (insulin-like growth factor 1) increases, incompatibility with other compounds (not seen with other aromatase inhibitors), and less negative effects on cholesterol levels (not seen with other aromatase inhibitors).

Aromasin Properties and Action

Aromasin is a steroidal suicide aromatase inhibitor.

This means that it has the characteristic 4-ring cycloalkane carbon structure that all steroid molecules have in common.

The fact that exemestane is a steroidal aromatase inhibitor is a major reason as to why it is a suicide aromatase inhibitor that permanently binds to the aromatase enzyme.

The aromatase enzyme is very attracted to the steroidal structure of androgens (testosterone), and the chemical structure of aromasin acts to 'trick' the aromatase enzyme into binding to estrogen, thereby inhibiting/deactivating it.

Because the binding strength is so strong, this inhibition of the aromatase enzyme to which aromasin binds is permanent.

Formestane, a similar steroidal aromatase inhibitor, exhibits the same properties (although it is much weaker and less potent than aromasin).

This is why there is no risk of estrogenic rebound when aromasin is abruptly stopped.

The other two major aromatase inhibitors (Arimidex and Letrozole) are non-steroidal aromatase inhibitors and are therefore associated with a risk of estrogen rebound after discontinuation.

This is because, unlike aromasin, they are not structurally similar to the target hormone of the aromatase enzyme.

Aromasin is a highly effective estrogen reducer at 25 mg daily, as demonstrated previously by its ability to reduce serum circulating estrogen levels by 85%.

Like other second-line breast cancer treatments, aromasin is very effective at lowering estrogen levels by inhibiting the aromatase enzyme, which is why, like Arimidex, it is only given to postmenopausal women or when other first-line breast cancer treatments have failed.

This is because postmenopausal women have very different changes in hormone levels and endocrine function compared to premenopausal women.

Both Arimidex and Letrozole are classified as non-steroidal and non-lethal aromatase inhibitors, which compete with substrates for binding to the enzyme's active site.

This is very different from aromasin (exemestane), which is a steroidal and suicidal aromatase inhibitor based on a mechanism that mimics the substrate and is converted by the enzyme into a reactive intermediate that inactivates the aromatase enzyme [3].

In layman's terms, this means that aromasin's chemical structure is similar to the traditional 'targets' that aromatase binds to (e.g. testosterone) and essentially 'tricks' the aromatase enzyme into binding to inhibit/inactivate it.

Because the binding strength is so strong, this inhibition of the aromatase enzyme that aromasin binds to is permanent.

Arimidex and Retro are non-lethal aromatase inhibitors, so instead of being guaranteed a permanent spot, they compete with the enzyme's traditional 'target' (this is where aromasin has an advantage over the other two).

Athletes, bodybuilders, and individuals using anabolic steroids will prefer aromasin as an aromatase inhibitor because it is useful in reducing, mitigating, and preventing estrogenic side effects.

These side effects occur as a result of the conversion (or conversion) of aromatizable androgens (such as testosterone) to estrogen, resulting in estrogen levels in the body that are much higher than normal physiological levels.

Aromasin (Exemestane) is a highly beneficial and preferred product among anabolic steroid users because it eliminates the problem of elevated estrogen levels at the root cause:

By binding to and inhibiting/neutralizing the aromatase enzyme, aromatizable androgens (testosterone, dianabol, boldenone, etc.) above physiological levels are not converted to estrogen, thus eliminating the risk of estrogen related side effects.

Aromasin Side Effects

Aromasin is known to be relatively well tolerated by most users.

However, it is not without potential side effects, and there are a few side effects of concern.

These are usually the result of estrogen levels decreasing too much or too quickly, or estrogen being suppressed for too long.

It is also important to understand that the use of aromasin (or aromatase inhibitors) has a greater side effect profile in women than in men.

The first aromasin side effect that individuals experience is joint and/or bone pain.

This is because estrogen plays a critical and important role in maintaining proper mineralization and bone density within bone tissue.

This is characteristic of all aromatase inhibitors, but aromasin has actually been shown in studies to strengthen bone tissue to some degree, whereas AIs like Arimidex (Anastrozole) and Letrozole (Femara) have been shown to severely reduce bone tissue.

Lethargy and fatigue are frequently reported side effects of aromasin and all other AIs.

Estrogen plays an important role in the central nervous system (CNS), and if estrogen levels become too low with any compound, it can cause daily chronic fatigue.

Restoring estrogen levels to normal physiological levels can alleviate this side effect.

Negative cholesterol changes are another important risk of using any AI, and aromasin is no exception.

Because estrogen plays an important role in maintaining proper cholesterol health, severe decreases in estrogen can negatively impact LDL and HDL levels.

However, aromasin has been shown in studies to have less negative effects than other aromatase inhibitors.

However, the risk still exists, so you should have regular checkups and blood tests.

The only aromasin side effect that can be considered unique to aromasin is the potential for androgenic side effects.

This may be due to the fact that aromasin is an androgenic steroid by its very structure.

Androgenic side effects can (and do) include increased oily skin (and resulting acne), increased facial and body hair growth, and in some cases, male pattern baldness (MPB) if genetic factors are present.

In addition, although not as severe as strong androgens such as Masteron (drostanolone), there may be a noticeable increase in aggression and drive with aromasin use.

Aromasin Dosing and Administration

Medically, aromasin is used as a second-line treatment for postmenopausal breast cancer patients when first-line treatment has failed. In this case, a dosage of 25 mg of aromasin per day is recommended for cancer treatment. The prescribing instructions also recommend that it be taken after meals.

Aromasin on-cycle for gynecomastia and estrogen control

For the treatment of gynecomastia and to keep estrogen under control during an anabolic steroid cycle, the average dosage is 12.5-25 mg per day.

Some users choose a protocol of 12.5 mg every other day, but this is highly dependent on the type and dosage of aromatizing steroids used.

Others keep aromasin on hand but choose not to use it unless they are experiencing estrogen related side effects or issues.

In this case, you may choose to take the full 25 mg until the side effects subside and then reduce the dosage to 12.5 mg per day, or 12.5 mg every other day, or even less.

Aromasin for post cycle therapy (PCT)

Studies have shown that aromasin can increase endogenous natural testosterone levels in men by as much as 60%, which is quite significant, especially in just 10 days.

The ideal dosage of aromasin for this purpose is 25 mg per day for no more than two weeks. Nolvadex is typically taken concurrently with aromasin for four weeks at a dose of 20-40 mg.

Aromasin has a half-life of approximately 27 hours.

It can be taken at any time of day, but research and prescribing guidelines suggest that aromasin may be better absorbed by the body if taken with food.

It's also important to understand that aromasin requires seven days for the body to reach peak plasma concentrations of the compound.

It is also very important to understand that for a compound like aromasin that reduces estrogen levels, the concept and idea here should be to control estrogen levels, not eliminate them.

Eliminating estrogen levels can have very dire consequences, especially in the long term.

Estrogen should only be controlled to appropriate levels if necessary, and aromatase inhibitors (such as Aromasin) should be stopped, discontinued, or greatly reduced in dosage.

Severely lowering estrogen levels will not only increase side effects, but will also negatively impact muscle gains in the long run.

Legality and Availability of Aromasin

Like many other ancillary compounds and anti-estrogens, aromasin is an uncontrolled substance in most countries around the world.

For example, in the United States and Canada, it is a prescription-only item, but it is not illegal to purchase, own, or possess aromasin in these countries, even if it is not an over-the-counter drug.

In many countries around the world, including Asia, the Middle East, and Eastern Europe, Aromasin is readily available over-the-counter for free.

Although Aromasin is a very widely used compound, for the time being it seems to be less popular than other aromatase inhibitors such as Aromasin and Letrozole, and this is most likely due to Aromasin being a late addition to the bodybuilding and anabolic steroid use scene.